AME 09:183-189 (1995)  -  DOI: https://doi.org/10.3354/ame009183

Observations on possible life cycle stages of the dinoflagellates Dinophysis cf. acuminata, Dinophysis acuta and Dinophysis pavillardi

Berland BR, Maestrini SY, Grzebyk D

Some aspects of the life-cycle have been investigated in Dinophysis cf. acuminata, the dominant species of the genus along the French Atlantic coast, as well as in D. acuta; a few observations have also been made on the Mediterranean species D. pavillardi. Dinophysis cells occur in 2 clearly distinguished sizes. Small cells typically had a theca thinner than large cells, and cingular and sulcal lists were less developed. Both small and large cells were seen dividing, producing 1 to 4 round intracellular bodies. Some of these round bodies in turn contained many small flagellated cells which escaped through a pore and swam rapidly. Their behaviour after release, and how they might give rise to vegetative cells, has not been observed thus far; we do not believe they are fungal parasites. We propose the following hypothesis to explain our observations: round-shaped bodies, formed inside the vegetative cells, produce small, motile zoids. These zoids grow and are transformed into apparently vegetative forms, which later act as gametes. Soon after conjugation, the zygote encysts, sometimes after the first or the second division. This working hypothesis, however, requires further elucidation and confirmation using different approaches.


Dinophysis sp. . Life cycle . Cyst


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